This invention relates to a limp, porous membrane of a sheet or cloth material and, more particularly, to a cloth material used as a membrane for a fluidized outlet in a covered hopper railway car.
It is known to use a cloth material in an outlet assembly for a covered hopper railway car. See, for example, U.S. Pat. No. 4,846,377 which is assigned to the same assignee as the present invention. However, while cloth membranes are advantageous, their usefulness has heretofore been limited. For example, the cloth membrane structure disclosed in this earlier patent shows installation of the membrane between the bottom of an outlet pan (7 in the patent drawings) and an outlet manifold (19 in the drawings). Such an assembly works well for certain types of outlets. Where, however, an outlet valve such a butterfly valve is positioned in the outlet, the installation shown in the '377 patent is not feasible. Nonetheless, it is still important to use a cloth membrane installation with such outlets so the advantages enumerated in the '377 patent can still be realized.